Enzyme-Powered Hollow Mesoporous Janus Nanomotors

The
development of synthetic nanomotors for technological applications
in particular for life science and nanomedicine is a key focus of
current basic research. However, it has been challenging to make active
nanosystems based on biocompatible materials consuming nontoxic fuels
for providing self-propulsion. Here, we fabricate self-propelled Janus
nanomotors based on hollow mesoporous silica nanoparticles (HMSNPs),
which are powered by biocatalytic reactions of three different enzymes:
catalase, urease, and glucose oxidase (GOx). The active motion is
characterized by a mean-square displacement (MSD) analysis of optical
video recordings and confirmed by dynamic light scattering (DLS) measurements.
We found that the apparent diffusion coefficient was enhanced by up
to 83%. In addition, using optical tweezers, we directly measured
a holding force of 64 ± 16 fN, which was necessary to counteract
the effective self-propulsion force generated by a single nanomotor.
The successful demonstration of biocompatible enzyme-powered active
nanomotors using biologically benign fuels has a great potential for
future biomedical applications.